NAME

Xephyr - X server outputting to a window on a pre-existing X display

SYNOPSIS

Xephyr [:display] [option...]

DESCRIPTION

Xephyr is a kdrive server that outputs to a window on a pre-existing
"host" X display. Think Xnest but with support for modern extensions
like composite, damage and randr.
Unlike Xnest which is an X proxy, i.e. limited to the capabilities of
the host X server, Xephyr is a real X server which uses the host X
server window as "framebuffer" via fast SHM XImages.
It also has support for "visually" debugging what the server is
painting.

OPTIONS

The server accepts all the standard options of Xserver(1) and the
following additional options:
-screenwidthxheight
sets the screen size.
-parentid
uses exiting window id. If a -screen argument follows a
-parent argument, this screen is embedded into the given
window.
-host-cursor
set 'cursor acceleration': The host's cursor is reused. This is
only really there to aid debugging by avoiding server paints
for the cursor. Performance improvement is negligible.

SIGNALS

Send a SIGUSR1 to the server (e.g. pkill -USR1 Xephyr) to toggle the
debugging mode. In this mode red rectangles are painted to screen
areas getting painted before painting the actual content. The delay
between this can be altered by setting a XEPHYR_PAUSE env var to a
value in micro seconds.

CAVEATS

o Rotated displays are currently updated via full blits. This is slower
than a normal orientated display. Debug mode will therefore not be of
much use rotated.
o The '-host-cursor' cursor is static in its appearance.
o The build gets a warning about 'nanosleep'. I think the various '-D'
build flags are causing this. I haven't figured as yet how to work
round it. It doesn't appear to break anything however.
o Keyboard handling is basic but works.
Mouse button 5 probably won't work.